1. Field of the Invention
This invention relates to highway delineator posts, and more particularly, to posts which are constructed to facilitate a breakover motion of an upper portion of the post upon impact by an automobile or other errant vehicle, so that damage to the vehicle and also to the delineator post is minimized.
2. Brief Description of the Prior Art
Highway delineator posts in current use generally include an elongated upright post structure susceptible to damage or destruction when struck by an errant automobile or other vehicle. The posts are generally constructed of metal, and are so severely bent upon impact by an automobile that repair by straightening, followed by relocation, is generally uneconomical, and the posts, after suffering such damage, are sold for scrap metal. The alternative to repair is replacement by a new post which is, of course, costly.
In an attempt to obviate the need for complete replacement and to reduce destruction, or the severity of damage, a number of articulated delineator post structures have been proposed which breakover or yield under impact. There have also been proposed several types of delineator posts having frangible sections which shear away under impact, but such devices still do not avoid or overcome the need for replacement, but merely are helpful in reducing the damage sustained by the automobile upon striking the delineator post.
One type of articulated structure which relies upon yielding or pivoting of an upper section of the post by the bending of a connecting bolt is that structure shown in Katt U.S. Pat. No. 3,820,906. In the Katt structure, impact to the upper portion of the post results in severance of a frangible plate along a shear line, followed by elongation and bending of a bolt used in supporting the upper portion of the post on a ground post or a lower section of the delineator post. It will be apparent that this structure, while yielding under impact and permitting less damage to be sustained by the upper portion of the post which is struck by the vehicle, nevertheless, requires repair and even replacement of certain portions of the articulation-affording portions of the post before the upper portion of the post can be placed back in service.
A breakaway sign post for use along highways is disclosed in King U.S. Pat. No. 3,521,917 and employs, in reducing damage to the sign post and to the automobile, a pair of yieldable, gripping side plates which are extended from the upper portion of the post over the opposite sides of a ground post, and which frictionally engage the ground post during the normal operating status of the post. When the upper portion of the post is impacted by an errant vehicle, the side plates can yield outwardly from each other to accommodate a pivoting motion of the upper portion of the post in which it is moved out of the vertical plane under the force of impact. Under severe impact, the upper portion of the post can be completely separated from the ground post upon which it is mounted. It will be perceived in referring to the King patent that an impact of any severity will sufficiently displace the upper portion of the post and that realignment and resetting of the upper portion of the post on the ground post is required before the sign post can be restored to operational status.
An example of a structural delineator post assembly which operates on the principle of the upper portion of the post being completely sheared away from a ground post and interconnecting coupling is that which is illustrated in Henry U.S. Pat. No. 3,628,296.
Yet another principle is illustrated in West German Pat. 1,459,830 where a plurality of snap-engaging brackets carried on an upper portion of a delineator post snap over a flange or plate carried at the upper side of the ground post and simply retain the upper portion of the post in vertical alignment with the ground post by a frictional snap-engagement. Impact imparted to the upper portion of the post will overcome the snap-engaging action of the brackets to completely release the upper portion of the post from the ground post. For reinstallation and restored service of the post assembly, it is then necessary for workmen to realign the spring-engaging brackets with the flange, and force the upper portion of the post downwardly until snap-engagement reoccurs. This assumes that the spring brackets are not distorted or bent when they are forced to yield by the sudden impact imparted to the upper portion of the post.
Other types of yieldable section or articulated highway post structures are shown in West German Pat. No. 1,255,128, Swiss Pat. No. 367,091, and Gubela U.S. Pat. No. 3,451,319.
In a different context, it is sometimes desirable to provide an articulated post structure, such as a flag pole, where the top end of a vertically extending pole can be made accessible by pivoting the top portion of the pole downwardly in relation to a ground post or anchoring structure to which it is pivotally secured when in use. Such structures, as previously proposed, which have included flag poles, are shown in Allen U.S. Pat. No. 3,792,680 and Crum U.S. Pat. No. 1,575,040. A fishing pole holder utilizing this general principle is shown in Hoover U.S. Pat. No. 3,539,080.
The Hoover fishing pole holder provides, through the use of resilient, inwardly curving clamping jaws in a tubular member retaining a pivoted portion of a fishing pole, a resilient snap-action which tends to snap the pivoted part of the pole into a position of axial alignment with the socket in which this part of the pole is mounted. This principle has not, however, been carried over or applied to any form of highway delineator post, and would actually be unsatisfactory for use in such application without the addition of some further structure making the pole and spring jaws (spring tubular member engaging the pole) compatible with a ground post to which the tubular member would be attached.
The highway delineator post structures hereinbefore described, and illustrated in the various patents referred to, while affording advantages over rigid posts which will not yield upon impact without destruction and severe damage to the automobile, nevertheless do not, in any instance, function in a way which minimizes or completely alleviates damage to the upper portion of the pole, and permits quick restoration to an operative status by unskilled workmen in a short period of time. In general, the prior art has not obviated the necessity for replacing or repairing the posts after high speed vehicle impact therewith. It therefore remains desirable to provide a highway delineator post which functions effectively as a marker and delineator along a highway, yet also reduces or eliminates the necessity for costly replacement or repair.